LOW SYMMETRICAL PHTHALOCYANINE ANALOGUES SUBSTITUTED WITH THREE CROWN ETHER VOIDS AND THEIR CATION-INDUCED SUPERMOLECULES

Unsymmetrical phthalocyanine analogues with three 15-crown-5 ether voids at the 3,4-positions (MtNIL, MtBZ, MtNAP) (Mt = Zn, Cu) have been synthesized and characterized. Their dimerization is induced by addition of some cations, particularly Rb2+ and K+. Cofacial dimer formation in the presence of these cations proceeds in a two-step three-stage process, as indicated by absorption and emission spectroscopy. These cofacial species have a highly specific C2v eclipsed configuration providing well-defined dimeric species for spectroscopic analysis. The ESR spectra of the cation-induced dimeric copper derivatives show axial symmetry and may be analyzed in terms of interplanar separation of 4.2 A. CuNAP alone forms a cofacial dimer even in the presence of Na+ or Cs+, and the estimated interplanar distances are 4.1−4.2 A without depending on the size of cations. The 1H NMR spectra of zinc dimers are consistent with a cofacial configuration. Magnetic circular dichroism (MCD) spectra of C2v type monomers can be in...